The electrophoretic deposition (EPD) process utilizes electric fields to deposit charged nanoparticles from a solution onto a substrate. Earlier industrial use of the EPD process employed organic solvent solutions and therefore typically generated hazardous waste as a by-product of the process. In addition, the shapes, compositions, densities, and microstructures of materials formed through EPD processes have typically been difficult if not impossible to control, either separately or in combination with one another. Also, it is extremely difficult to form structures from more than one material. That is to say, typical EPD processes are limited in that they are only capable of forming planar, homogenous structures.
Recent nanomaterial work has demonstrated that EPD can, at small length scales, be performed using aqueous (water-based) solutions. EPD has been used with a wide range of nanoparticles including, but not limited to, oxides, metals, polymers, semiconductors, and even diamond. Advanced EPD formation techniques may be able to achieve even more useful products, such as ceramics and cermets.